Bump minimum git version to v2.31.0

With git v2.31.0, several new features have been introduced which Gitaly
wants to make use of:

    - Passing git configuration via a new set of enviroment variables
      `GIT_CONFIG_COUNT`, `GIT_CONFIG_KEY_$n` and `GIT_CONFIG_VALUE_$n`.
      This allows us to configure credentials without leaking them via
      the command line.

    - Atomic fetches, which allow us to make use of transactions when
      fetching many references via git-fetch(1).

    - A performance optmization for fetches from a repository which has
      a huge amount of references.

Gitaly will thus bump the minimum required git version to v2.31.0. As a
preparatory step, this commit updates GitLab to start requiring this
version.

.gitlab-ci.yml

@@ -17,7 +17,7 @@ stages:
 # in cases where jobs require Docker-in-Docker, the job
 # definition must be extended with `.use-docker-in-docker`
 default:
-  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.14-git-2.29-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-11-graphicsmagick-1.3.36"
+  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.14-git-2.31-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-11-graphicsmagick-1.3.36"
   tags:
     - gitlab-org
   # All jobs are interruptible by default

.gitlab/ci/frontend.gitlab-ci.yml

@@ -15,7 +15,7 @@
   extends:
     - .frontend-base
     - .assets-compile-cache
-  image: registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2-git-2.29-lfs-2.9-node-14.15-yarn-1.22-graphicsmagick-1.3.34
+  image: registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2-git-2.31-lfs-2.9-node-14.15-yarn-1.22-graphicsmagick-1.3.36
   variables:
     WEBPACK_VENDOR_DLL: "true"
   stage: prepare

.gitlab/ci/global.gitlab-ci.yml

@@ -87,7 +87,7 @@
     policy: pull
 
 .use-pg11:
-  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.14-git-2.29-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-11-graphicsmagick-1.3.36"
+  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.14-git-2.31-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-11-graphicsmagick-1.3.36"
   services:
     - name: postgres:11.6
       command: ["postgres", "-c", "fsync=off", "-c", "synchronous_commit=off", "-c", "full_page_writes=off"]
@@ -96,7 +96,7 @@
     POSTGRES_HOST_AUTH_METHOD: trust
 
 .use-pg12:
-  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.14-git-2.29-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-12-graphicsmagick-1.3.36"
+  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.14-git-2.31-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-12-graphicsmagick-1.3.36"
   services:
     - name: postgres:12
       command: ["postgres", "-c", "fsync=off", "-c", "synchronous_commit=off", "-c", "full_page_writes=off"]
@@ -105,7 +105,7 @@
     POSTGRES_HOST_AUTH_METHOD: trust
 
 .use-pg11-ee:
-  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.14-git-2.29-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-11-graphicsmagick-1.3.36"
+  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.14-git-2.31-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-11-graphicsmagick-1.3.36"
   services:
     - name: postgres:11.6
       command: ["postgres", "-c", "fsync=off", "-c", "synchronous_commit=off", "-c", "full_page_writes=off"]
@@ -116,7 +116,7 @@
     POSTGRES_HOST_AUTH_METHOD: trust
 
 .use-pg12-ee:
-  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.14-git-2.29-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-12-graphicsmagick-1.3.36"
+  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.14-git-2.31-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-12-graphicsmagick-1.3.36"
   services:
     - name: postgres:12
       command: ["postgres", "-c", "fsync=off", "-c", "synchronous_commit=off", "-c", "full_page_writes=off"]

changelogs/unreleased/pks-git-minimum-v2-31-0.yml

+---
+title: Bump minimum git version to v2.31.0
+merge_request: 58737
+author:
+type: changed

lib/system_check/app/git_version_check.rb

@@ -7,7 +7,7 @@ class GitVersionCheck < SystemCheck::BaseCheck
       set_check_pass -> { "yes (#{self.current_version})" }
 
       def self.required_version
-        @required_version ||= Gitlab::VersionInfo.parse('2.29.0')
+        @required_version ||= Gitlab::VersionInfo.parse('2.31.0')
       end
 
       def self.current_version